Surface modification of calcium sulfate whisker prepared from flue gas desulfurization gypsum

Liu, Chengjun; Zhao, Qing; Wang, Yeguang; Shi, Peiyang; Jiang, Maofa

doi:10.1016/j.apsusc.2015.11.032

Cited by 57 publications

(26 citation statements)

References 9 publications

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“…These results, combined with the XRD patterns in Figure 2, showed three characteristic peaks at 11.62 • , 20.72 • , and 29.11 • for FGD gypsum, indicating that the main component of the raw material is calcium sulfate dihydrate (CSD). Many literature studies have revealed that CSD can easily dehydrate into products with improved performance under specific conditions [37,38]. In this paper, the major product in CSHW is pure α calcium sulfate hemihydrate (α-CSH), which has been verified by the XRD pattern in Figure 2 and TG/DTA curve in Figure 3.…”

Section: Basic Characteristics Of Cshwsupporting

confidence: 60%

Calcium Sulfate Hemihydrate Whiskers Obtained from Flue Gas Desulfurization Gypsum and Used for the Adsorption Removal of Lead

Wang

et al. 2017

Crystals

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As a recycled material, flue gas desulfurization gypsum has been used to prepare calcium sulfate hemihydrate whisker (CSHW) through hydrothermal synthesis for several decades. However, the subsequent utilization of this resultant material has not yet received considerable attention. In the present research, CSHW was successfully synthesized at a certain region, and was used for the adsorption of lead ions from aqueous solutions, thereby broadening the research field for the practical application of CSHW. Its adsorption capacity was significantly influenced by various parameters, particularly, the pH level and initial lead concentration. The pH value highly affected the hydrolysis degree of lead ions and dominated the adsorption of lead. The equilibrium isotherms under two different temperatures were simulated using Langmuir, Freundlich, and Temkin models. Both Langmuir and Temkin models showed a good fit to the data. Combined with the well-fitted pseudo-second-order model, the adsorption mechanism was thought to be a chemisorption process that was enforced by the ion exchange reaction. In addition, the specific crystal structure of CSHW revealed that ion exchange reaction occurred on the (010) and (100) facets due to their preferential growth and negatively charged property. The residual solid phase after adsorption was collected and detected using X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. Results revealed that PbSO 4 was formed on the surface of CSHW. The alkaline condition introduced the tribasic lead sulfate, and thus reduced the stability of the adsorption system.

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Section: Basic Characteristics Of Cshwsupporting

confidence: 60%

Calcium Sulfate Hemihydrate Whiskers Obtained from Flue Gas Desulfurization Gypsum and Used for the Adsorption Removal of Lead

Wang

et al. 2017

Crystals

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“…However, all of these products are low value-added. And the emergence of calcium sulfate whiskers (a new type of α- CaSO 4 ·0.5H 2 O) with high added value has attracted tremendous interests of researchers due to the excellent performance in thermal stability, chemical resistance and mechanical strength 5 – 8 . The inexpensive whiskers, which can obviously enhance the mechanical properties of rubbers, plastics, adhesives and papers 9 – 14 , have great potential to become ideal reinforcing materials.…”

Section: Introductionmentioning

confidence: 99%

A facile method of transforming FGD gypsum to α-CaSO4·0.5H2O whiskers with cetyltrimethylammonium bromide (CTAB) and KCl in glycerol-water solution

Guan

Sun

et al. 2017

Sci Rep

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A facile method to transform flue gas desulfurization gypsum (FGD gypsum) to α- calcium sulfate hemihydrate (α-HH) whiskers with high aspect ratios mediated by cetyltrimethylammonium bromide (CTAB) and KCl in glycerol-water solutions was studied. Addition of KCl facilitated the dissolution of calcium sulfate dihydrate (DH) and created a much higher supersaturation, which could come into being a larger driving force for the phase transformation from DH to α-HH. CTAB as the crystal modifier can significantly promoted 1-D growth of α-HH whiskers along the c axis and the presence of 0.25% CTAB (by weight of FGD gypsum) resulted in the increase of the average aspect ratio of α-HH whiskers from 28.9 to 188.4, which might be attributed to the preferential adsorption of C16H33(CH3)3N+ on the negative side facets of α-HH crystal.

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“…Due to their easy availability and high efficiency, silane coupling agents have been widely used as surface modifier . Significantly, the hydrophobicity of inorganic whisker surface has been improved after the simple surface modification with silane coupling agents.…”

Section: Introductionmentioning

confidence: 99%

Surface modification of calcium sulfate whisker using thiol‐ene click reaction and its application in reinforced silicone rubber

Chen

Ding

Dong

et al. 2020

Journal of Polymer Science

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The hemihydrate calcium sulfate whisker (HCSW) was modified by γ‐(methacryloxy)propyl trimethoxy silane (KH570) and trimethylolpropane tris(3‐mercaptopropionate) via wet modification and thiol‐ene click reaction, and then the unmodified and modified HCSW were added into α, ω‐dihydroxy polysiloxane (DPS) matrix to prepare silicon rubber composites. After the dual‐surface modification, the surface of HCSW was transformed to hydrophobic, the hydration of whisker was obviously improved, and the whisker dispersed more evenly in the polymer. The mechanical properties, dynamic mechanical properties, and the medium resistance of the silicone rubber composite were compared. The tensile test shows that the silicone rubber shows better mechanical properties after adding the modified whiskers, among which HCSW‐KH570‐SH has the most significant reinforcement effect. Moreover, DPS/HCSW‐KH570‐SH shows the best medium resistance in toluene, gasoline, and water. The addition of modified whiskers can improve the storage modulus of silicone rubber significantly, while DMA and DSC show that the addition of modified whiskers can reduce the glass transition temperature of silicone rubber. The bound rubber indicates that the interface interaction between HCSW‐KH570‐SH and silicone rubber is the best.

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Surface modification of calcium sulfate whisker prepared from flue gas desulfurization gypsum

Cited by 57 publications

References 9 publications

Calcium Sulfate Hemihydrate Whiskers Obtained from Flue Gas Desulfurization Gypsum and Used for the Adsorption Removal of Lead

Calcium Sulfate Hemihydrate Whiskers Obtained from Flue Gas Desulfurization Gypsum and Used for the Adsorption Removal of Lead

A facile method of transforming FGD gypsum to α-CaSO4·0.5H2O whiskers with cetyltrimethylammonium bromide (CTAB) and KCl in glycerol-water solution

Surface modification of calcium sulfate whisker using thiol‐ene click reaction and its application in reinforced silicone rubber

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